The present invention is generally directed to multistage thermoelectric devices, and more particularly, to thick-film based multistage thermoelectric micro-coolers.
In a typical thermoelectric cooling device, a current of electrons flows from a p-type semiconductor material to an n-type material. During this transition at least some of the electrons will increase their energy state by absorbing thermal energy. This increased energy is lost as heat as the current flows through a subsequent conductor or converse junction. The net result is a temperature gradient that can extract heat from an object to be cooled.
Current thermal-mechanical cooling devices, such as Stirling coolers and Joule-Thompson coolers, typically exhibit a significant reduction in their efficiency as their sizes decrease. As such, these devices—though relatively efficient at macroscale—are difficult to scale down to micro-scale sizes. Moreover, the large sizes of conventional commercially available multistage thermoelectric coolers—which are typically formed by vertical stacking of a series of individual thermoelectric coolers—limit their efficiency and the types of applications for which they are suited. In addition, such multistage coolers are generally fabricated by utilizing cumbersome serial—and often manual—assembly processes.
Accordingly, there is a need for enhanced cooling devices, especially for generating cryogenic temperatures. In particular, there is a need for better multistage thermoelectric coolers, and more efficient methods for their fabrication.